Attachment method between heat exchanger parts

ABSTRACT

A process of connecting a header pipe of a heat exchanger to another heat exchanger part, including the steps of (a) providing a header pipe with a hole in its side and cladding material about its circumference, and a part with a groove with flux applied to the portion of the part to be joined to the header pipe, (b) positioning the header pipe and the part to align the header pipe hole and part groove, (c) inserting a rivet into the aligned header pipe hole and part groove, (d) locating a supporting rod in the header pipe and aligned with the rivet, and (e) hammering the part to warp the head of the rivet against the supporting rod and widen the circumference of the rivet in the hole and groove.

CROSS REFERENCE TO RELATED APPLICATION(S)

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable:

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

TECHNICAL FIELD

The present invention relates to a process for assembling a heatexchanger, and more particularly to a process for attaching fixtures tothe header pipe.

BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIORART

Heat exchangers for air circulating systems of automobiles, for example,are constructed with a header pipe installed on the heat exchanger corewhich has cooling fluid tubes and cooling fins. The brackets and otherinlet/outlet fixtures for cooling liquid are initially attached to theheader pipe on a heat exchanger frame during the assembly of suchcomponents, after which they often are permanently attached to theheader pipe through brazing, while cladding material is applied.

Various technical suggestions have heretofore been proposed to assist ininitial assembly fo such heat exchangers. Korean Practical New DeviceRegistration Number 10-1996-38332, for example, suggests creating aconjunctional vacuum between the tank of the header pipe and the bracketas they are aligned, including riveting after a rivet is inserted intothe conjunctional vacuum. Korean Practical New Device RegistrationNumber 10-1996-67450 has also suggested creating a conjunctional vacuumbetween the tank of the header pipe and the bracket as they are aligned.While maintaining this vacuum, the bottom portion of a conjunctionalmaterial is inserted into the tank or the bracket, and then is tightlyfixed.

The above technical suggestions can be advantageous when used with thinbrackets and fixtures. However, they become problematic when the rivetsand the conjunctional materials are applied to thick fixtures. Inaddition, since the rivet and the bottom portion of the conjunctionalmaterial are exposed on the exterior, it damages the externalappearance.

According to another technical suggestion, the header pipe is TIG weldedto the header pipe and the other fixtures including brackets. However,with this method, if the electrical current fluctuates during thewelding, the depth and the height of the bead will change, creating aproblem with the bracket coming off during the core brazing. Moreover,in the case of large fixtures in which the entire circumferences of morethan two parts must be welded, the cost of the method can be high.

The present invention is directed toward overcoming one or more of theproblems set forth above.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a process of connecting a headerpipe of a heat exchanger to another heat exchanger part is provided,including the steps of (a) providing a header pipe with a hole in itsside and cladding material about its circumference, and a part with agroove with flux applied to the portion of the part to be joined to theheader pipe, (b) positioning the header pipe and the part to align theheader pipe hole and part groove, (c) inserting a rivet into the alignedheader pipe hole and part groove, (d) locating a supporting rod in theheader pipe and aligned with the rivet, and (e) hammering the part towarp the head of the rivet against the supporting rod and widen thecircumference of the rivet in the hole and groove.

In one form of this aspect of the present invention, the hammering stepalso compresses the rim of the header pipe hole.

In another form of this aspect of the present invention, the supportingrod has a curved surface at its contacting point to the rivet during thehammering step.

In still another form of this aspect of the present invention, ⅕ to ½ ofthe length of the rivet is in the part groove before the hammering step.In a further form, the depth of the part groove is in the range of ⅕-½of the entire length of the rivet before the hammering step.

In yet another form of this aspect of the present invention, the rivetis one of a plain rivet, a round headed rivet and a rivet with knurlingon the end in the part groove.

In still another form of this aspect of the present invention, the rivetis round headed, and the supporting rod has a concave groovecorresponding to the rivet round head at the portion that contacts thehead of the rivet during the hammering step.

In another aspect of the present invention, a process of connecting aheader pipe of a heat exchanger to another heat exchanger part isprovided, including the steps of (a) forming (I) a hole in the headerpipe with cladding material about the hole circumference, and (ii) agroove in the part with flux applied to the portion of the part to bejoined to the header pipe, (b) aligning the header pipe hole and thepart groove with a rivet inserted in the aligned header pipe hole andpart groove, (c) locating a supporting rod in the header pipe, and (d)hammering the part to warp the head of the rivet against the supportingrod and widen the circumference of the rivet in the hole and groove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a header pipe and part adapted forassembly according to the method of the present invention;

FIG. 2 is a cross-sectional view showing the header pipe and the partbeing aligned with a rivet;

FIG. 3 is a cross-sectional view showing riveting by hammering of thepart according to the method of the present invention.

FIG. 4 is a cross-sectional view after the riveting is completed;

FIG. 5 is a cross-sectional view of an alternative embodiment of thepresent invention in which a rivet with a round head is used;

FIG. 6 is a cross-sectional view similar to FIG. 3, but showing rivetingby hammering of the part with the FIG. 5 embodiment; and

FIG. 7 is a cross-sectional view similar to FIG. 3, but of still anotherembodiment of the present invention in which a rivet with a knurledportion is used.

DETAILED DESCRIPTION OF THE INVENTION

Broadly, according to the present invention, components of a heatexchanger are attached by, in a first phase, creating a hole in theheader pipe with cladding material applied on its circumference, andcreating a groove in the opposite part while flux is applied to theportion of the opposite part which will be fixed to the header pipe.Thereafter, a rivet is inserted into the hole and the groove while theheader pipe and the opposite part are positioned with both the hole andthe groove aligned. A supporting rod is then put into the header pipefacing the head of the rivet and, by hammering the part, the head of therivet is warped to compress the rim of the pipe hole while also wideningthe circumference of the rivet until it fully fills the hole and thegroove, resulting in complete tightness.

The Figures illustrate this process.

FIG. 1, which shows a cross-sectional view of the first phase of theinvention, illustrates hole 10 is created in the header pipe 12 of aheat exchanger (not shown). At the same time, a groove 20 is formedrespectively in the assembly part 22, matching the hole 10 of the headerpipe 12. The assembly part 22 (i.e., the part attached to the chassis ofthe heat exchanger) mounted to the header pipe 12 can be any bracket, orany inlet/outlet fixture in which the cooling fluid flows in/out.

As mentioned above, with the hole 10 in the header pipe 12 and thegroove 20 in the part 22, cladding materials 30 can be applied both tothe header pipe 12 and the joining section of the part 22 (since brazingwill be performed later). Otherwise, cladding material 30 may be appliedonly to the joining section (which will be joined to the part 22 of theheader pipe 12), with flux 40 applied to the joining section (which willbe joined to the header pipe 12) of the part 22. Thus, by applyingeither cladding material 30 or flux 40, during the brazing, the clad 30and the flux 40 will be melted by the heat. In the end this will resultin tight adhesion.

During the second phase of the process of the present invention, theheader pipe 12 and the part 22 are positioned with the hole 10 of theheader pipe 12 and the groove 20 of the part 22 aligned, and a rivet 50is inserted through the hole 10 and the groove 20.

Thereafter in the third phase, as shown in FIG. 3, a supporting rod 60is inserted into the header pipe 12 so as to contact the head of therivet 50, and the part 22 is hammered with a puncher 70 to perform ariveting process. The head portion of the rivet 50 which is contactedwith the supporting rod 60 is warped by this process, filling the hole10 and tightening the rim around the hole 10. At the same time, as thecircumference of the inserted portion of the rivet 50 in the groove 20expands, it fully fills the groove 20, as shown in the FIG. 4.

The surface of the supporting rod 60 which connects to the rivet 50 mayadvantageously be curved according to the inner shape of the header pipe12. The attachment formed using a supporting rod 60 having such asurface will advantageously be tight since, when the part 22 is beinghammered, the warped portion of the rivet 50 will tighten around the rimof the hole 10 of the header pipe 12 between the curved surface of thesupporting rod 60 and inner surface of the header pipe 12.

It should be appreciated that, since the riveting was done inside theheader pipe 12 and part 22, none of the rivet portion 50 is externallyexposed from either the header pipe 12 or the part 22. In addition,since a groove 20 is made in part 22 instead of a hole, this method canbe readily used with a heavy sectioned part where making a hole may bevery difficult.

It should also be appreciated that the diameters of the hole 10 in theheader pipe 12 and the groove 20 in the part 22 should be chosen withconsideration to the size of the applied rivet 50. The diameter of therivet 50 compared to the diameter of the hole 10 and the diameter of thegroove 20 should be selected so that there is not too much loosenessduring riveting, to thereby ensure that the process of the presentinvention will result in secure and tight attachments. For example,during the process of inserting the rivet into the hole and the groove,the portion inserted into the groove 20 may advantageously be betweenabout ⅕ to ½ of the total length of the rivet. If the inserted portionof the rivet 50 exceeds more than about ½ of the total length of therivet 50, the header pipe 12 and the part 22 may be damaged (due to therepetitive hammering of the part 22 in order to expand the circumferenceof the inserted portion of the rivet 50 sufficiently to fill the groove20). Moreover, since there is limitation to the expansion of thecircumference of the rivet 50, if the inserted portion of the rivet 50exceeds more than ½ of the total length of the rivet 50, the desiredtight adhesion will not occur. On the other hand, if the inserted lengthof the rivet 50 is less than about ⅕ of its total length, completefilling cannot be expected. In order to achieve the above-mentionedrange, the groove 20 may be formed so that it has a depth according tothe given range, or the size of the rivet 50 can be chosen according tothe given range.

In summary, FIGS. 1-4 show one practical implementation of the inventionof the present invention using a plain rivet 50, FIGS. 5-7, by contrast,illustrate the implementation of the present invention using differentrivets, specifically, a rivet 80 having a round head 81 (FIGS. 5-6) anda rivet 90 with knurling 91 (FIG. 7).

Thus, in the case of applying the round headed rivet 80 as shown on theFIG. 5, the supporting rod 60′ may advantageously include acorresponding concave groove 94 in the shape of the round head 81 of therivet 80. The rivet 80 then can be inserted through the header pipe 12to the groove 20 of the part 22 as the head 81 of the rivet is alreadyinserted to the concave groove 94 of the supporting rod 60′. After that,as shown in FIG. 6, the part 22 is hammered with the puncher 70 in theriveting process. It should be appreciated that, besides the roundheaded rivet 80, various other types of rivet (e.g., an oval-headedrivet) could also be used within the scope of the present invention.

As shown on the FIG. 7 (where a rivet 90 with knurling 91 is used), theknurled portion 91 of the rivet 90 is inserted into the groove 20 of thepart 22. During the process of riveting, by hammering the part 22, theknurled portion 91 will be caused to warp the inner surface of thegroove 20, creating a tight connection. At the same time, since the widesurface of the knurling 91 will fill the groove 20 more fully, it maycreate a more solid tightening than in the case of using a plain rivet.

It should thus be appreciated that the attachment method between partsof the heat exchanger according to the present invention assures thevery firm assembly of the header pipe and the part. During the processof the riveting, the circumference of the rivet expands, filling andjoining tightly both the hole of the header pipe and the groove of thepart. Likewise since this solid attachment is possible, making theriveting section in the center of the part will hold the assemblystrongly enough, while at the same time reducing the cost. Furthermore,this invention will greatly improve the quality of the heat exchangersince the assembly part is adhered tightly and safely to the headerpipe.

Further, because a groove instead of a hole is made in the part, thepresent invention may be advantageously used with heavy sectioned partswhere making a hole is very difficult. Moreover, since the riveting isdone inside of both the header pipe and the part, no portion of therivet is exposed to the exterior, thus preserving the externalappearance.

Still further, it should thus be appreciated that the present inventionprovides a method of attaching heat exchanger components at a low costduring the provisional assembly of various parts of the header pipe(including the brackets and the inlet/outlet fixtures of cooling fluid).

Still other aspects, objects, and advantages of the present inventioncan be obtained from a study of the specification, the drawings, and theappended claims. It should be understood, however, that the presentinvention could be used in alternate forms where less than all of theobjects and advantages of the present invention and preferred embodimentas described above would be obtained.

1. A process of connecting a header pipe of a heat exchanger to anotherheat exchanger part, comprising the steps of: providing a header pipewith a hole in its side and cladding material about its circumference,and a part with a groove with flux applied to the portion of the part tobe joined to the header pipe; positioning the header pipe and the partto align the header pipe hole and part groove; inserting a rivet intothe aligned header pipe hole and part groove; locating a supporting rodin the header pipe and aligned with the rivet; and hammering the part towarp the head of the rivet against the supporting rod and widen thecircumference of the rivet in the hole and groove.
 2. The process ofclaim 1, wherein said hammering step also compresses the rim of theheader pipe hole.
 3. The process of claim 1, wherein the supporting rodhas a curved surface at its contacting point to the rivet during thehammering step.
 4. The process of claim 1, wherein before the hammeringstep, ⅕ to ½ of the length of the rivet is in the part groove.
 5. Theprocess of claim 4, wherein the depth of the part groove is in the rangeof ⅕-½ of the entire length of the rivet before the hammering step. 6.The process of claim 1, wherein the rivet is one of a plain rivet, around headed rivet and a rivet with knurling on the end in the partgroove.
 7. The process of claim 1, wherein the rivet is round headed,and the supporting rod has a concave groove corresponding to the rivetround head at the portion that contacts the head of the rivet during thehammering step.
 8. A process of connecting a header pipe of a heatexchanger to another heat exchanger part, comprising the steps of:forming a hole in the header pipe with cladding material about the holecircumference, and a groove in the part with flux applied to the portionof the part to be joined to the header pipe; aligning the header pipehole and the part groove with a rivet inserted in the aligned headerpipe hole and part groove; locating a supporting rod in the header pipe;and hammering the part to warp the head of the rivet against thesupporting rod and widen the circumference of the rivet in the hole andgroove.